ScholarWorks@UMassAmherst

Recent Submissions

  • PublicationOpen Access
    A Study of Cake Porosities in Constant Rate Expression
    (1979-05) Abularach, Victor Hugo
    Constant rate expression of fluid from deformable particulate solids was studied at pressing speeds of 2 and 5 cm/min. Spent drip-grind and high-temperature extracted coffee grounds were used as test materials. The cell walls of the latter were partly hydrolyzed as result of the extraction process. Comparison of the results obtained with these two types of grounds and with fluid viscosities of 1 and 15 CP made possible a qualitative analysis of the effect of cell wall permeability on the cake porosity. A technique was developed to measure the cake porosity as a function of the cake specific volume. The particles were contained in a cylindrical expression cell, and the extraparticle void space was filled with a tracer solution of known concentration. As the particles were compressed, exudation of intracellular fluid begun and the tracer solution was diluted. The extend of dilution was monitored at the outflow and measured by spectrophotometric techniques. Initial compation resulted mainly in a reduction of the extraparticle void volume, followed by exudation and particle collapse. In the case of drip-grind coffee grounds, exudation started at a cake specific volume of 4.2 cc/g. In the case of high-temperature extracted coffee grounds, exudation begun at an earlier stage of compaction (higher specific volume). The cake porosities were calculated from a mass balance on the tracer. With drip-grind grounds as the test material, cake porosities were found to decrease at first with compaction, to a value of 0.3 at a cake specific volume of 2.5 cc/g, and increased to 0.37 with further compaction. When the fluid viscosity was increased by soaking the grounds in a 50% by weight sucrose solution, this increase in porosity was not observed. With high-temperature extracted grounds as the test material, a minimum porosity of 0.3 was also observed, but at a cake specific volume of 3.7 cc/g. In this case further compaction also resulted in an increase in porosity to 0.37 at maximum compaction. There was no significant difference between results obtained at pressing speeds of 2 and 5 cm/min. The cake porosity data were used in the Kozeny-Carman equation to predict the fluid pressure drop across the cake. There was lack of agreement between the calculated pressure drops and direct measurements obtained in parallel investigations. This disagreement was mainly the result of a change in particle sphericity with compaction. The exudation pressure drop was calculated from the rate of intracellular fluid exudation. It was assumed that during compaction there is no cell rupture, and that exudation takes place through the coffee cell pores on the surface of the particle, and that the flow can be satisfactorily described by Poiseuille’s law. This model of exudation was found to be inappropriate because considerable cell rupture occurs during cake compaction.
  • PublicationOpen Access
    Student Perspectives on Chat GPT
    (2023-08) Bello, Anne Pence; Davidson, Skylar; DiMarco-Crook, Christina; Kuusinen, Colleen; LaChance, Anna Marie; Light, Erica; Mei, Siobhan; Miller, Becky; McDougal Ronconi, Julia; Tooker, Nicholas; Trust, Torrey
    Chat GPT, a generative AI technology was introduced in November 2002. Academic discussion about potential student use and potential abuse of Chat GPT was prevalent at introduction. However, actual student use of Chat GPT was unknown. In May 2023, we surveyed 614 predominantly-STEM undergraduate students at a R1 public university in the Northeastern United States about their use of Chat GPT. We asked qualitative questions about how and why they use Chat GPT as well as reason for not using ChatGPT. Apriori coding was used to code student responses. Forty-one percent of students has used Chat GPT to help with some aspect of their academic work. Most students used the technology ethically, to support learning and identified utility and ease as the primary motivation for use. Concerns about academic integrity were prevalent in users and non-users of Chat GPT, indicating a desire for ethical use of the technology.
  • PublicationOpen Access
    Elect a Candidate with GenAI
    (University of Massachusetts Amherst, 2026-06) Maloy, Robert; Trust, Torrey
    This digital choice board invites students to develop AI literacy skills as they design a campaign to elect a candidate to a local or state political office. Activities include using GenAI to analyze voting patterns, design campaign materials, produce videos, raise funds, create an AI transparency statement, and more.
  • PublicationMetadata only
    Utilizing Slow Reading Techniques to Promote Deep Learning
    (2023-05-31) Baldi, Brian; Mejia, Cynthia
    Slow reading has long been viewed as a teaching technique that engages students more deeply with course readings. Little systematic research, however, has been done to understand how this pedagogical strategy works in college classrooms. This study investigated how slow reading techniques promoted deep learning among undergraduate college students across two disciplines. Utilizing two food essays as the basis for a reading assignment, students in two courses participated in an intentionally scaffolded and paced slow reading exercise designed to encourage deeper personal engagement with course concepts. Theoretical implications from the research demonstrate connections between slow reading techniques and the existing literature on both significant and deep learning. More practically, this study found that slow reading techniques fostered personal storytelling as a means of developing deeper connections to assigned texts, presenting an opportunity for instructors hoping to facilitate the meaningful integration of course concepts into students’ lives.
  • PublicationOpen Access
    Internet Success: A Study of Open-Source Software Commons
    (2012) Schweik, Charles; English, Robert C.